This project proposes to investigate the feasibility of utilizing high molecular weight polysaccharide (PS) antigens found in the cultural supernatants of P. aeruginosa as a vaccine against infections caused by this organism. These antigens are isolated by a method developed by the principal investigator, then characterized chemically, biophysically, and serologically. Animals are then used to test the immunogenicity and protective efficacy of the PS antigens. Specific goals include chemical characterizations of PS antigens isolated from a number of different serotypes of P. aeruginosa, commencement of structural studies on at least one of these antigens, further purification of these antigens to determine to most active component(s), and development of a vaccine formula based on the serologic diversity of these antigens. Finally, studies on the response of infected patients to these PS antigens will be done in order to assess the immune response of individuals to these antigens.